SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc235f23ed56da6363efc13215d98f16c35ac14015f0e1106a1f99964feeef7f' 
  AND token = '5qaC/0EE3tB195KcM422dpaqfz6bBesnN9dZtqnW0vA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}